A wig is, in general, made up with a wig base mainly comprising artificial skin made of soft plastic material or net member and a number of hairs implanted to said wig base. If ventilation and lightness are aimed when a wig is worn, it has to be taken into consideration to make the weight of hair implanted to a wig base lighter, as well as how to make lighter the weight of a wig base. In order to make a lighter wig base, various technical developments have been tried, such as taking off a part of a wig base made of artificial skin, for example, a top part or both side parts, and connecting net member to said taken off part, thus making a wig base having partial net member, or making a whole wig base with net member, and reinforcing the rim by fringing with artificial skin made of synthetic plastics. Also, there are various wig bases such as that the hair line region of which is made of net member in order to attain the lightness and ventilation of a wig, and natural looking of hair line, as disclosed, for example, in Japanese Patent Preliminary Publication No. JP S62-215002A.
Meanwhile, in order to wear such a wig on a head, the backside of a wig base and the head must be firmly bonded with bonding means so that the wig does not scoot from the head or come off easily. As the conventional bonding means, commercially available liquid or viscous adhesive, commercial double-stick adhesive tape, or a clip specifically for binding a wig have been used, and a wig is fixed on to a head by either of these means. Put-on and take-off of a wig are made easier by using a clip specifically for binding a wig. A typical clip is such that fixes the inversion part provided with a plurality of comb-tooth like tips to the backside of a wig base, and binds to the wearer's own hair by inserting said tips to the hair, and utilizing the inversion action of the inversion part. Such a clip is not suitable to the case that the remaining hair is few at the fixing position of the head, since it is to utilize the wearer's own hair.
When liquid or viscous adhesive is used to bond a wig to the head, since it is applied between the head skin and the backside of a wig base and bond them, these for medical application which are inactive to skin and do not tend to cause such inflammation as rash are used. However, when a wig is taken off, since the adhesive stuck on the head skin has to be removed with peeling agent such as thinner, the skin tends to be damaged both physically and chemically, and taking-off itself is laborious.
In case of double-stick adhesive tape, peeling agent is almost not required, and put-on and take-off of a wig are easier than the case using liquid or viscous adhesives. As double-stick adhesive tape, a core material of polyethylene film of about 30 μm thickness is commercially available, of which both faces are coated with adhesive, and bonded with peeling paper, and which is rolled up. Said rolled up double-stick adhesive tape is cut to appropriate length, and the peeling paper is removed. Then one side of adhesive faces is bonded to the reinforcing material made of plastics attached to the backside of a wig base made of artificial skin or of net member, for example, at four places forth and back, left and right, and the other side of adhesive faces is bonded to the head skin or the hair so that the wig is fixed. As the layer thickness of the adhesive of double-stick adhesive tape, about 30 to 50 μm of low allergic acrylic medical adhesive is usually used, and is applied evenly to both sides of said core material.
In case that a whole or a part of a wig base is made of net member (This may be called hereinafter a net base.), the filament of nylon, polyester, or the like with diameter of about 100 to 150 μm as net base is used, and a sheet with network having rhomboidal or rectangular spaces is formed with said filament, a net base is formed with said sheet to a shape fit to the wearer's head shape, and a wig is made up with said net base with a number of hair implanted thereto. A wig wearer pulls outward the periphery of a net base so that it does not wrinkle or loosen, and fixes on to the head using a binder attached to the desired position of the backside of a net base, liquid or viscous adhesive applied to the head skin, or double-stick adhesive tape.
Since a wig is thus worn by pulling a net base in peripheral direction by applying external force, excess pulling tension is applied to the net base comprising thin filaments, thereby the net base may be distorted or broken. Therefore, it is required to fix the reinforcement member made of more or less hard plastics to the certain portion of a net base where load tends to be applied, particularly to its peripheral portion. Further in addition, in order to apply adhesive or attach a clip to the desired portion of the backside of a net base, it is necessary to make a bonding seat as the bonding means with another material such as soft plastics or cloths, and to fix said bonding seat to the predetermined portion of the backside of net base. Since said bonding seats are for attaching adhesive or a clip, they are generally made thick of another broad plastics or cloths, and are sewn firmly to several peripheral portions of the backside of a net base, thereby these parts can not help but become heavy and thick. Also, by setting the above-mentioned reinforcement members or bonding seats to a net base, the network of these parts are choked, thereby ventilation is interfered, and causes stuffiness, distortion, or deterioration.
Thus, it is preferred not to provide reinforcement members or bonding seats, in case lightness and ventilation of a net base are to be considered as important. If, for this reason, a bonding means is to be attached directly to a net base without reinforcement members or bonding seats, nothing but double-stick adhesive tape can be used as such bonding means instead of instant adhesive or a clip. Because, if a clip is directly set to the filaments of small diameter making up net base, said clip must be bound and sewn to a plurality of filaments, holding tight the clip to wearer's own hair while pulling a net base to peripheral direction causes excess tension to thin filaments, which results in dissociation of cross points of filaments, cutting off the filaments themselves, and ultimately the breach of the net base. In addition, said clip can be easily seen through hairs from the outside of a wig. On the other hand, if head skin or hair and a net base are tried to be directly adhered with liquid or viscous adhesive, the filaments of a net base and the wearer's head practically contact only linearly, and only such linear contact between filaments and a head causes easy scooting from the head, and therefore is not suitable to practical use.
Therefore, the inventors tried to bond directly, by using the commercially available medical double-stick adhesive tape, one side of adhesive surfaces to the desired position of the backside of a net base. In this case, one side of adhesive surfaces of double-stick adhesive tape was bonded directly to each filament making up a net base, and the other adhesive surface of double-stick adhesive tape was bonded to a wearer's head skin and hairs. If a wig is firmly fixed to a head when thus bonded, then the reinforcing material of plastics or cloth and a bonding seat are not required to be attached to the backside of a wig base, and hence sufficient ventilation and also reducing weight can be attained.
However, the various repeated experiments by the inventors made it clear that the attempt of direct bonding of one side of adhesive surfaces of double-stick adhesive tape to net base resulted in bonding only on linear contact as in the case of liquid or viscous adhesive, since the cross section of a filament making up a net was circular. This is because the thickness of one side of adhesive layers of commercially available medical double-stick adhesive tape is about 30 to 50 μm, whereas the filaments of 100 to 150 μm are usually used since the filament making up net base needs certain strength, so that pressing the adhesive layer of double-stick adhesive tape to net base causes only linear bonding along one side of the filament with a circular cross section.
Also in addition to it, it became clear that, since the network formed among crossing filaments, that is, net mesh was vacant space, most of adhesive surface was not utilized, and bonding was effected only in linear direction of a filament, so that adhesion was weak, and the worn wig easily came off a head. This was also a case when the adhesiveness of double-stick adhesive tape was enriched. Thus, it was confirmed that applying commercially available medical double-stick adhesive tape to a wig of net base proved to be impractical, as the bonding of adhesive to net base was too weak.
A wig was also test made with said commercially available medical double-stick adhesive tape applied to the backside of a net base, and its worn state was observed from outside, then head skin could be seen through hairs implanted to the net base from the network of each crossing filament, and said smooth side of adhesive surfaces of double-stick adhesive tape shone through network of each filament, which was recognized by an observer as unnatural reflection, and the part of adhesive surface was seen as floating up white due to this glossiness, resulting in easy recognition of the presence of double-stick adhesive tape.
Thus, wearing a wig comprising a net base on a head by using double-stick adhesive tape proved to have such problems as, sufficient bonding force could not be attained because only linear adhesion to net base was effected, and since adhesive surface of double-stick adhesive tape was smooth, the light which passed through a wig reflected on said smooth adhesive surface of double-stick adhesive tape bonded on the backside of net base, causing the presence of double-stick adhesive tape to be recognized through the hair of a wig.
The objective of the present invention is, referring to the problems mentioned above, to provide double-stick adhesive tape for wig bonding having sufficient adhesive force to a wig base comprising a net base, whereas not easily visible upon wearing, as well as a wig provided with said double-stick adhesive tape which has good appearance.